The practical mechanism of backet excavation is so complicated that the larger scale model apparatus would be suitable for the experimental study.
So authors presented in this paper the test results and the empirical equation on the backet exacavation with the larger scale model.
　In this experiment, 0.015m3 backts were used and both sides of them were made of parallel plates.
　The experiment was carried out under the conditions that,
　soil;two kinds of sand
　running velocity; 1.5-6.0 (m/min)
　revolution; 2.5-5.0 (r.p.m)
　The physical characteristics of sand were measured with the vane test (M) or the cone penetration test, (P).
　Then we got the following empirical equation on the horizontal component of excavation force.
　where C;constant
　　　A;constant relating to revolution
　　　V;running velocity (m/min)
　　　N;revolution (r.p.m)
　　　D;excavtion depth (cm)
　In this experiment two exponents were as follows.
　　　n1= 1.16
　　　n2= 1.30